Dielectrics are non-conducting fluids used in a variety of applications. The insulative and cooling properties of dielectric fluids find use in electrical components such as transformers, capacitors, switching gears, transmission components, distribution components, switches, regulators, circuit breakers, autoreclosers, fluid-filled transmission lines, and other electrical apparatuses.
In a transformer, the dielectric fluid provides coolant and insulative properties to the internal transformer components. The dielectric fluid cools the transformer and also provides part of the electrical insulation between internal live parts. Requirements for dielectric fluid include a long operating life (10-20 years) and stability at high temperatures (above ambient) for an extended period.
Polychlorinated biphenyl compounds (also known as “PCB's”), once used as dielectric fluid in transformers, have been phased out due to their toxic properties and negative environmental impact. Non-toxic transformer oils that have replaced PCB's include silicone-based or fluorinated hydrocarbon oils, mineral oils, fatty acid esters, vegetable-based oils and seed oils. These non-toxic oils have drawbacks regarding viscosity, flash point, fire point, pour point, water saturation point, dielectric strength and/or other properties limiting their usefulness as dielectric fluids.
Consequently, a need exists for a non-toxic, biodegradable, PCB-free dielectric fluid for electrical components that have the same, or substantially the same, chemical, mechanical, and/or physical properties as PCB-based dielectric fluid.